Browsing by Author "Shastri, Yogendra"
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Item Open Access Cost reduction approaches for fermentable sugar production from sugarcane bagasse and its impact on techno-economics and the environment(Springer, 2021-05-18) Baral, Pratibha; Munagala, Meghana; Shastri, Yogendra; Kumar, Vinod; Agrawal, DeeptiIn an enzymatically driven lignocellulosic biorefinery, pretreatment and hydrolysis modules are the two most significant cost contributors for obtaining high gravity sugar solutions. The present study aimed to reduce the use of alkali and Cellic CTec2 during the bioprocessing of sugarcane bagasse (SCB). Later its impact on the overall process economics and the environment was evaluated. During pretreatment, solid loading of 15% (w/w) and use of 2% (w/v) sodium hydroxide at 121 °C for 30 min emerged as an optimum strategy. It resulted in > 65% delignification of SCB, retaining ≥ 90% and 65% of glucan and xylan fraction, respectively, in the pretreated biomass. Two approaches were evaluated in parallel to minimize the requirement of this commercial cellulase enzyme blend. The first strategy involved its partial replacement with an in-house enzyme cocktail by blending. The second route was performing hydrolysis with reduced loadings of cellulase enzyme blend above its optimum temperature, which gave more promising results. Hydrolysis of 20% alkali pretreated SCB with cellulase enzyme blend dosed at 15 mg protein g−1 glucan led to 84.13 ± 1 and 83.5 ± 2.3% glucan and xylan conversion yields respectively in 48 h at 52.5 °C. The filtrate and wash fraction contained ≥ 165 and ≥ 65 g L−1 sugar monomers representing glucose and xylose. However, in both the fractions > 75%, sugar accounted for glucose. The techno-economic analysis revealed that the sugar production cost from SCB was 1.32 US$/kg, with the optimized bioprocess. Environmental impact study showed that the process contributed to 1.57 kg CO2 eq in terms of climate change.Item Open Access Economic and environmental assessment of succinic acid production from sugarcane bagasse(American Chemical Society, 2021-09-15) Shaji, Arun; Shastri, Yogendra; Kumar, Vinod; Ranade, Vivek V.; Hindle, NeilThis work presents technoeconomic analysis (TEA) and life cycle assessment (LCA) of a novel biorefinery producing succinic acid (SA) from sugarcane bagasse. The process consists of acid pretreatment, fermentation, followed by downstream separation and purification. Experimental data for pretreatment and fermentation are adapted for a plant processing 4 t/h of dry bagasse, producing 405 kg/h of succinic acid with the same quantity of acetic acid as a side product. Downstream separation is simulated in ASPEN PLUS. The facility is assumed to be annexed to and heat-integrated with an existing sugar mill in India. LCA is performed considering cradle-to-gate scope with 1 kg of SA as the functional unit. The TEA results show that although the process is currently not economically feasible, expected improvements in fermentation yields will make it cost-competitive. For the expected yield, the product cost of SA is INR 121/kg ($1.61/kg), and the selling price of succinic acid should be INR 178/kg ($2.37/kg) for a payback period of 4 years. Pretreatment and fermentation are the biggest contributors to the product cost. The life cycle greenhouse gas (GHG) emissions are 1.39 kg of CO2 equiv/kg succinic acid with electricity as the major contributor. Process improvement opportunities are identified to reduce the costs, as well as life cycle impacts.Item Open Access Sugarcane bagasse valorization to xylitol: techno-economic and life cycle assessment(Wiley, 2022-04-17) Shaji, Arun; Shastri, Yogendra; Kumar, Vinod; Ranade, Vivek V.; Hindle, NeilA detailed techno-economic analysis and life cycle assessment (LCA) of a novel bio-refinery that produces xylitol from sugarcane bagasse are provided. The proposed process includes dilute acid pretreatment in pressurized conditions followed by fermentation (upstream section). The fermentation broth is then sent for separation and purification to the downstream section. Calculations are performed for a plant with 4 t/h of dry bagasse throughput. With a fermentation yield of 0.54 g xylitol per g of xylose, the plant produced 437.4 kg/h of xylitol. Upstream data are adapted from experimental studies, while ASPEN PLUS® flowsheet simulation is used to obtain data for the downstream section. The xylitol production facility is assumed to be annexed to an existing sugar mill in India. The total utility requirement in the process is reduced using heat integration strategies. Cradle-to-gate scope is considered for the LCA and 1 kg of xylitol is taken as the functional unit. The product cost of xylitol is calculated to be 230 INR/kg (US$3.17/kg). For a 4 year payback period, the selling price of xylitol must be 450 INR/kg (US$6.2/kg). The fermentation and pretreatment sections are the major components of the product cost. The LCA results show that the life cycle greenhouse gas emissions are 2.759 kg CO2 eq. per kg xylitol. The electricity requirement within the plant is identified as the major source of greenhouse gas emissions, and reduction of fermentation duration is identified as a key factor. The results identify opportunities to improve the process from an economic as well as an environmental standpoint. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.